The prior art is rich with approaches to measurement of bone characteristics using acoustic and other methods with a view to identifying patients in need of treatment for osteoporosis. Many acoustic techniques utilize a first transducer to provide an acoustic signal, typically at ultrasonic frequencies, to the subject from a first external location and a second transducer at a second external location disposed on the opposite side of the bone of interest to receive the signal transmitted by the first transducer through the bone and intervening soft tissue. The transducers are often coupled to the subject through a suitable fluid, such as water, or gel. Related techniques are described, for example, in U.S. Pat. No. 5,720,290, issued Feb. 24, 1998, entitled "Apparatus and Method for Acoustic Analysis of Bone Using Optimized Functions of Spectral and Temporal Signal Components," which is hereby incorporated herein by reference. It is known that the derivation of clinically useful data may require highly reproducible measurements across both population samples and from measurement to measurement within an individual.